Commit 65710cb6 authored by Ming Lei's avatar Ming Lei Committed by Greg Kroah-Hartman
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firmware loader: simplify pages ownership transfer 



This patch doesn't transfer ownership of pages' buffer to the
instance of firmware until the firmware loading is completed,
which will simplify firmware_loading_store a lot, so help
to introduce the following cache_firmware and uncache_firmware
mechanism during system suspend-resume cycle.

In fact, this patch fixes one bug: if writing data into
firmware loader device is bypassed between writting 1 and 0 to
'loading', OOPS will be triggered without the patch.

Also handle the vmap failure case, and add some comments to make
code more readable.

Signed-off-by: default avatarMing Lei <ming.lei@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3cd52ab6

drivers/base/firmware_class.c

+39 −23
Original line number Original line Diff line number Diff line
@@ -93,6 +93,8 @@ struct firmware_priv { 
	struct completion completion;

	struct completion completion;

	struct firmware *fw;

	struct firmware *fw;

	unsigned long status;

	unsigned long status;

	void *data;

	size_t size;

	struct page **pages;

	struct page **pages;

	int nr_pages;

	int nr_pages;

	int page_array_size;

	int page_array_size;
@@ -156,9 +158,11 @@ static void fw_dev_release(struct device *dev) 
	struct firmware_priv *fw_priv = to_firmware_priv(dev);

	struct firmware_priv *fw_priv = to_firmware_priv(dev);

	int i;

	int i;





	/* free untransfered pages buffer */

	for (i = 0; i < fw_priv->nr_pages; i++)

	for (i = 0; i < fw_priv->nr_pages; i++)

		__free_page(fw_priv->pages[i]);

		__free_page(fw_priv->pages[i]);

	kfree(fw_priv->pages);

	kfree(fw_priv->pages);



	kfree(fw_priv);

	kfree(fw_priv);





	module_put(THIS_MODULE);

	module_put(THIS_MODULE);
@@ -194,6 +198,7 @@ static ssize_t firmware_loading_show(struct device *dev, 
	return sprintf(buf, "%d\n", loading);

	return sprintf(buf, "%d\n", loading);

}

}





/* firmware holds the ownership of pages */

static void firmware_free_data(const struct firmware *fw)

static void firmware_free_data(const struct firmware *fw)

{

{

	int i;

	int i;
@@ -237,9 +242,7 @@ static ssize_t firmware_loading_store(struct device *dev, 




	switch (loading) {

	switch (loading) {

	case 1:

	case 1:

		firmware_free_data(fw_priv->fw);

		/* discarding any previous partial load */

		memset(fw_priv->fw, 0, sizeof(struct firmware));

		/* If the pages are not owned by 'struct firmware' */

		for (i = 0; i < fw_priv->nr_pages; i++)

		for (i = 0; i < fw_priv->nr_pages; i++)

			__free_page(fw_priv->pages[i]);

			__free_page(fw_priv->pages[i]);

		kfree(fw_priv->pages);

		kfree(fw_priv->pages);
@@ -250,20 +253,6 @@ static ssize_t firmware_loading_store(struct device *dev, 
		break;

		break;

	case 0:

	case 0:

		if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {

		if (test_bit(FW_STATUS_LOADING, &fw_priv->status)) {

			vunmap(fw_priv->fw->data);

			fw_priv->fw->data = vmap(fw_priv->pages,

						 fw_priv->nr_pages,

						 0, PAGE_KERNEL_RO);

			if (!fw_priv->fw->data) {

				dev_err(dev, "%s: vmap() failed\n", __func__);

				goto err;

			}

			/* Pages are now owned by 'struct firmware' */

			fw_priv->fw->pages = fw_priv->pages;

			fw_priv->pages = NULL;



			fw_priv->page_array_size = 0;

			fw_priv->nr_pages = 0;

			complete(&fw_priv->completion);

			complete(&fw_priv->completion);

			clear_bit(FW_STATUS_LOADING, &fw_priv->status);

			clear_bit(FW_STATUS_LOADING, &fw_priv->status);

			break;

			break;
@@ -273,7 +262,6 @@ static ssize_t firmware_loading_store(struct device *dev, 
		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);

		dev_err(dev, "%s: unexpected value (%d)\n", __func__, loading);

		/* fallthrough */

		/* fallthrough */

	case -1:

	case -1:

	err:

		fw_load_abort(fw_priv);

		fw_load_abort(fw_priv);

		break;

		break;

	}

	}
@@ -299,12 +287,12 @@ static ssize_t firmware_data_read(struct file *filp, struct kobject *kobj, 
		ret_count = -ENODEV;

		ret_count = -ENODEV;

		goto out;

		goto out;

	}

	}

	if (offset > fw->size) {

	if (offset > fw_priv->size) {

		ret_count = 0;

		ret_count = 0;

		goto out;

		goto out;

	}

	}

	if (count > fw->size - offset)

	if (count > fw_priv->size - offset)

		count = fw->size - offset;

		count = fw_priv->size - offset;





	ret_count = count;

	ret_count = count;
@@ -396,6 +384,7 @@ static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj, 
		retval = -ENODEV;

		retval = -ENODEV;

		goto out;

		goto out;

	}

	}



	retval = fw_realloc_buffer(fw_priv, offset + count);

	retval = fw_realloc_buffer(fw_priv, offset + count);

	if (retval)

	if (retval)

		goto out;

		goto out;
@@ -418,7 +407,7 @@ static ssize_t firmware_data_write(struct file *filp, struct kobject *kobj, 
		count -= page_cnt;

		count -= page_cnt;

	}

	}





	fw->size = max_t(size_t, offset, fw->size);

	fw_priv->size = max_t(size_t, offset, fw_priv->size);

out:

out:

	mutex_unlock(&fw_lock);

	mutex_unlock(&fw_lock);

	return retval;

	return retval;
@@ -504,6 +493,29 @@ static void _request_firmware_cleanup(const struct firmware **firmware_p) 
	*firmware_p = NULL;

	*firmware_p = NULL;

}

}





/* transfer the ownership of pages to firmware */

static int fw_set_page_data(struct firmware_priv *fw_priv)

{

	struct firmware *fw = fw_priv->fw;



	fw_priv->data = vmap(fw_priv->pages, fw_priv->nr_pages,

				0, PAGE_KERNEL_RO);

	if (!fw_priv->data)

		return -ENOMEM;



	fw->data = fw_priv->data;

	fw->pages = fw_priv->pages;

	fw->size = fw_priv->size;



	WARN_ON(PFN_UP(fw->size) != fw_priv->nr_pages);



	fw_priv->nr_pages = 0;

	fw_priv->pages = NULL;

	fw_priv->data = NULL;



	return 0;

}



static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,

static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent,

				  long timeout)

				  long timeout)

{

{
@@ -549,8 +561,12 @@ static int _request_firmware_load(struct firmware_priv *fw_priv, bool uevent, 
	del_timer_sync(&fw_priv->timeout);

	del_timer_sync(&fw_priv->timeout);





	mutex_lock(&fw_lock);

	mutex_lock(&fw_lock);

	if (!fw_priv->fw->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))

	if (!fw_priv->size || test_bit(FW_STATUS_ABORT, &fw_priv->status))

		retval = -ENOENT;

		retval = -ENOENT;



	/* transfer pages ownership at the last minute */

	if (!retval)

		retval = fw_set_page_data(fw_priv);

	fw_priv->fw = NULL;

	fw_priv->fw = NULL;

	mutex_unlock(&fw_lock);

	mutex_unlock(&fw_lock);

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